Wrist exerciser



FIG. 1 is a front view of a wrist exerciser showing my new design, the rear view being identical;

FIG. 2 is a right side view thereof, the left side view being identical;

FIG. 3 is a top plan view thereof, the bottom plan view being identical, and,

FIG. 4 is a perspective view thereof. 

The ornamental design for a wrist exerciser, as shown. 